Open Access Theses and Dissertations

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You searched for +publisher:"Georgia Tech" +contributor:("Dr. Haskell W. Beckham"). Showing records 1 – 2 of 2 total matches.

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Georgia Tech

1. Nam, Sunghyun. Dynamics of Cyclic and Linear Poly(oxyethylene) and Threading Conformation in Their Blends.

Degree: PhD, Textile and Fiber Engineering, 2006, Georgia Tech

URL: http://hdl.handle.net/1853/14135 

Chemically identical but topologically different cyclic and linear polymers not only result in marked differences in dynamics, but also lead to unique transport properties of their blends, where cyclic polymers have chances to be threaded onto the linear polymers. This dissertation addresses the effect of ring architecture on dynamics using different time/length scale techniques: self-diffusion coefficients, NMR spin-spin relaxation time (T2) and bulk viscosity. In deuterated water, synthesized cyclic poly(oxyethylene) (CPOE) (400-1500 g/mol) diffused faster than corresponding linear POE (LPOE) and linear POE dimethyl ether (LPOEDE). However, the self-diffusion coefficients in melts were arranged in the following manner: LPOEDE > CPOE > LPOE, in excellent agreement with T2 and viscosity data, showing topological and chain end effects. Compared to LPOEDE, both CPOE and LPOE had higher activation energies for viscosity with less dependence on the molecular weight. In the blends of CPOE and LPOE for 900 and 1500 g/mol, the diffusion coefficient and viscosity in melts were higher and lower than the values predicted by a binary mixing rule, respectively. These deviations were attributed to the threading conformation, and the weight fraction of the threaded chains for 1500 g/mol was estimated by a three-term mixing rule. This threading conformation also appeared to influence such important bulk properties as the glass transition and spherulitic growth rate of the blends. Advisors/Committee Members: Dr. Haskell W. Beckham (Committee Chair), Dr. David G. Bucknall (Committee Member), Dr. Johannes Leisen (Committee Member), Dr. Rigoberto Hernandez (Committee Member), Dr. Victor Breedveld (Committee Member).

Subjects/Keywords: Spherulitic growth rate of cyclic polymer; Blends of cyclic and linear polymers; Topological effect on the dynamics; Self-diffusion coefficient; Diffusion of threaded chains; Polymers Testing; Polymers Viscosity

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Nam, S. (2006). Dynamics of Cyclic and Linear Poly(oxyethylene) and Threading Conformation in Their Blends. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/14135

Chicago Manual of Style (16th Edition):

Nam, Sunghyun. “Dynamics of Cyclic and Linear Poly(oxyethylene) and Threading Conformation in Their Blends.” 2006. Doctoral Dissertation, Georgia Tech. Accessed April 16, 2021. http://hdl.handle.net/1853/14135.

MLA Handbook (7th Edition):

Nam, Sunghyun. “Dynamics of Cyclic and Linear Poly(oxyethylene) and Threading Conformation in Their Blends.” 2006. Web. 16 Apr 2021.

Vancouver:

Nam S. Dynamics of Cyclic and Linear Poly(oxyethylene) and Threading Conformation in Their Blends. [Internet] [Doctoral dissertation]. Georgia Tech; 2006. [cited 2021 Apr 16]. Available from: http://hdl.handle.net/1853/14135.

Council of Science Editors:

Nam S. Dynamics of Cyclic and Linear Poly(oxyethylene) and Threading Conformation in Their Blends. [Doctoral Dissertation]. Georgia Tech; 2006. Available from: http://hdl.handle.net/1853/14135


Georgia Tech

2. Hillock, Alexis Maureen Wrenn. Crosslinkable Polyimide Mixed Matrix Membranes for Natural Gas Purification.

Degree: PhD, Chemical Engineering, 2005, Georgia Tech

URL: http://hdl.handle.net/1853/13933 

Crosslinkable mixed matrix membranes represent an attractive technology that promises both outstanding separation properties and swelling resistance for the purification of natural gas. This approach relies upon dispersal of a CO2/CH4 size-discriminating zeolite in a crosslinkable polymer, which is resistant to CO2 swelling when crosslinked. The resulting membrane has the potential to separate CO2 from CH4 more effectively than traditional pure polymer membranes, while also providing needed membrane stability in the presence of aggressive CO2-contaminated natural gas streams. Control studies are conducted using the pure crosslinkable polymer to observe the separation properties and swelling resistance. Initial crosslinkable mixed matrix membrane experiments are then performed and result in an increase in membrane productivity, instead of the expected increase in selectivity. Traditionally, this is caused by material incompatibility at the polymer/zeolite interface, so the crosslinkable mixed matrix membranes are characterized to examine this issue. During the material characterization, a new non-ideal transport phenomenon is discovered in the zeolite phase. A model is developed to better understand the transport and predict subsequent experimental results. Once the independent materials are proven to be viable, crosslinkable mixed matrix membranes that show enhancements in both efficiency and productivity and exhibit stability in the presence of aggressive CO2 feeds are created. Advisors/Committee Members: Dr. William J. Koros (Committee Chair), Dr. Christopher W. Jones (Committee Member), Dr. Haskell W. Beckham (Committee Member), Dr. Ronald W. Rousseau (Committee Member), Dr. Stephen J. Miller (Committee Member).

Subjects/Keywords: Crosslinked polyimide; Gas separation; Natural gas purification; Zeolite mesoporosity; Mixed matrix

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Hillock, A. M. W. (2005). Crosslinkable Polyimide Mixed Matrix Membranes for Natural Gas Purification. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/13933

Chicago Manual of Style (16th Edition):

Hillock, Alexis Maureen Wrenn. “Crosslinkable Polyimide Mixed Matrix Membranes for Natural Gas Purification.” 2005. Doctoral Dissertation, Georgia Tech. Accessed April 16, 2021. http://hdl.handle.net/1853/13933.

MLA Handbook (7th Edition):

Hillock, Alexis Maureen Wrenn. “Crosslinkable Polyimide Mixed Matrix Membranes for Natural Gas Purification.” 2005. Web. 16 Apr 2021.

Vancouver:

Hillock AMW. Crosslinkable Polyimide Mixed Matrix Membranes for Natural Gas Purification. [Internet] [Doctoral dissertation]. Georgia Tech; 2005. [cited 2021 Apr 16]. Available from: http://hdl.handle.net/1853/13933.

Council of Science Editors:

Hillock AMW. Crosslinkable Polyimide Mixed Matrix Membranes for Natural Gas Purification. [Doctoral Dissertation]. Georgia Tech; 2005. Available from: http://hdl.handle.net/1853/13933

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